1. Field of the Invention
The present invention relates to a one-way clutch used in an automatic transmission, or the like, and a mounting structure of the oneway clutch.
2. Related Background Art
For instance, in a oneway clutch disclosed in the Japanese Patent Application Laid-Open No. 2002-39222, a large number of lock members such as sprags or rollers are provided between an outer race and an inner race to be supported by a retainer, and end bearings are disposed on the both sides thereof in the axial direction.
The oneway clutch is used in various uses as a mechanical element. Particularly, when the one-way clutch is used in an automatic transmission as means for latching a rotational element of a planetary gear for constituting a gear change mechanism on to a transmission case, a latched state of the rotational element on to the transmission case can be automatically released by a reverse rotation of a torque which is applied on the rotational element, dissimilarly from a frictional engagement element of a multiple disc wet structure. As a result, the oneway clutch is effectively used as latching means which brings one of different rotational elements into engagement and, at the same time, releases the engagement when a speed changing operation is performed for releasing the other of the rotational elements.
There is conventionally disclosed a technology for assembling and supporting such a oneway clutch in a transmission in the Japanese Patent Application Laid-Open No. 2002-39222. In this Japanese Patent Application Laid-Open No. 2002-39222, it is arranged such that a play of a fitting portion on either an outer race or an inner race, whichever is connected to a case, is reduced (that is, a large movement in the radial direction of the outer race which always stands still is restricted by reducing a play with the case) and a large load in the radial direction is not applied on an end bearing. As a result, the surface pressure to be applied on the end bearing can be reduced and the durability of the oneway clutch can be improved. Also, since a radial movement of a rotational member which is fitted with the inner race is absorbed by the play of the fitting portion with the inner race, the force of inertia acting in the radial direction on the rotational member does not act on the inner race, so that the surface pressure acting on the end bearing can be reduced and the durability of the oneway clutch is improved.
Also, in the Japanese Patent Application Laid-Open No. 2002-39222, it is possible to further reduce the surface pressure applied on the end bearing by substantially eliminating the play in the fitting portion between the outer race and the case since the load in the radial direction applied on the outer race but also the dead load thereof is supported on the case through a contact portion of a spline. Moreover, since the end bearing is arranged to be located on the inner peripheral side than the outer race so as to support only the inner race having a smaller mass, the surface pressure acting on the end bearing can be further reduced.
As described above, the Japanese Patent Application Laid-Open No. 2002-39222 discloses a structure for mounting the oneway clutch by the use of an end bearing.
However, there are some oneway clutches which have no end bearing, but in which the dead load is applied onto a rotational member. Furthermore, an outer race member or an inner race member onto which such a load is applied may be abraded.
Also, to obtain the structure disclosed in the Japanese Patent Application Laid-Open No. 2002-39222, it is necessary to machine the teeth of the spline with certain precision. To machine the tooth bottom portions of the spline is not easy because a working tool is required to be put to each of the tooth bottom portions, which requires a considerable processing time. Accordingly, for a oneway clutch with this structure, it is inevitably required to form these tooth bottom portions requiring high precision on either one of a stationary member and the outer race member.
In view of the above circumferences, it is an object of the present invention to reduce a load to be applied onto an outer race member or an inner race member which is mounted on a rotational member so as to prevent abrasion of whichever member suffering this load. It is another object of the present invention to provide a oneway clutch and a mounting structure of the oneway clutch in which a stationary member and a support reference surface of the outer race member or the inner race member to be mounted on the stationary member can be processed or machined easily.
In order to solve the above problems, according to the present invention, there is proposed a mounting structure of a oneway clutch comprising an outer race member and an inner race member either of which is mounted on a stationary member and the other of which is mounted on a rotational member, wherein                a bearing means other than an end bearing is interposed between said outer race member and said inner race member; and        a clearance between said stationary member and said one member is smaller than a clearance between said rotational member and said other member.        
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that said one member is restricted and supported in the radial direction by said stationary member.
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that said one member which is mounted on said stationary member is provided with an arcuate support reference surface which is drawn around the center of said member, and a radial positioning is performed by restricting and supporting said support reference surface.
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that cam surfaces are formed on said one member and a cylindrical surface is formed on the other member.
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that said one member is the outer race member and the other member is the inner race member.
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that said one member is supported in the axial direction by said stationary member with a stop ring.
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that said one member is provided with an engagement projection to be fitted in said stationary member.
Also, in the mounting structure of a one-way clutch of the present invention, it is preferable that at least one of said outer race member and said inner race member is provided with an oil path for supplying a lubricating oil to said cam surfaces or said cylindrical surface.
Also, according to a second aspect of the invention, there is provided a oneway clutch in which either one of an outer race member and an inner race member is mounted on a stationary member and the other is mounted on a rotational member, wherein:                said one member mounted on the stationary member is provided with an arcuate support reference surface around the center of said one member.        
In the oneway clutch of the second aspect of the invention, it is preferable that said support reference surface is circular.
In the oneway clutch of the second aspect of the invention, it is preferable that said one member is provided with an engagement projection which is fitted in said stationary member.
In the oneway clutch of the second aspect of the invention, it is preferable that said support reference surface and said engagement projection are disposed at different positions, respectively, seen in the axial direction.
In the oneway clutch of the second aspect of the invention, it is preferable that said one member is provided with cam surfaces and the other member is provided with a cylindrical surface.
In the oneway clutch of the second aspect of the invention, it is preferable that said one member is the outer race member and the other member is the inner race member.
In the oneway clutch of the second aspect of the invention, it is preferable that between said outer race member and said inner race member there are provided rollers serving as torque transmission members and a retainer for retaining said rollers and means for biasing said rollers in the direction of engagement.
In the oneway clutch of the second aspect of the invention, it is preferable that a block bearing is provided between said outer race member and said inner race member.
In the oneway clutch of the second aspect of the invention, it is preferable that at least one of said outer race member and said inner race member is provided with an oil path for supplying a lubricating oil to said cam surfaces or said cylindrical surface.